<template>
  <div class="score-case">
    <div class="table">
      <table>
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>考试时间</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody>
          <!-- 1.将list渲染到页面 -->
          <tr v-for="(item,index) in list" :key="item.id">
            <td>{{index+1}}</td>
            <td>{{item.subject}}</td>
            <!-- 2.如果分数小于60才有red类名 -->
            <td :class="{red:item.score<60}">{{item.score}}</td>
            <td>{{FormData(item.date)}}</td>
            <!-- 删除并阻止默认行为 -->
            <td @click.prevent="delFn(item.id)"><a href="#">删除</a></td>
          </tr>
          <!-- <tr >
            <td>2</td>
            <td>数学</td>
            <td>100</td>
            <td>Tue Jun 07 2022 10:00:00 GMT+0800 (中国标准时间)</td>
            <td><a href="#">删除</a></td>
          </tr> -->
        </tbody>
        <tbody v-show="list.length===0">
          <tr>
            <td colspan="5">
              <span class="none">暂无数据</span>
            </td>
          </tr>
        </tbody>
        <tfoot v-show="list.length > 0">
          <tr>
            <td colspan="5">
              <span>总分：{{totalScore}}</span>
              <span style="margin-left:50px">平均分：{{avgScore}}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>
    <div class="form">
      <div class="form-item">
        <div class="label">科目：</div>
        <div class="input">
          <!-- 双向绑定科目并去除首尾空格 -->
          <input type="text" placeholder="请输入科目" v-model.trim="subject"/>
        </div>
      </div>
      <div class="form-item">
        <div class="label">分数：</div>
        <div class="input">
          <!-- 双向绑定分数并转数字类型 -->
          <input type="text" placeholder="请输入分数" v-model.number="score"/>
        </div>
      </div>
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button class="submit" @click="addFn">添加</button>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
// 1.安装moment  yarn add moment
// 2.引入时间 
import moment from 'moment'
export default {
  name: 'ScoreCase',
  data () {
    return {
      list:
        // 获取的时候转成对象
        JSON.parse(localStorage.getItem('scoreList'))||[],
      
      // list: [
      //   {id: 15, subject: '语文', score: 89, date: new Date('2022/06/07 10:00:00')},
      //   {id: 27, subject: '数学', score: 100, date: new Date('2022/06/07 15:00:00')},
      //   {id: 32, subject: '英语', score: 56, date: new Date('2022/06/08 10:00:00')},
      //   {id: 41, subject: '物理', score: 76, date: new Date('2022/06/08 10:00:00')}
      // ],
      subject: '',
      score: ''
    }
  },
  methods: {
   delFn(id) {
    //filter过滤筛选满足条件的 如果当前遍历的id不等于当前点击的id则满足条件
      this.list=this.list.filter(item=>item.id!==id)
   },
   addFn() {
    if(this.score>=0&&this.score<=100&&this.subject) {
      this.list.push({
          // at(-1)最后一个id
          // 如果list数组里面有元素，就用最后一个元素的id+1
          // 如果没有就让新增的元素的id为1
        id:this.list.length ? this.list.at(-1).id + 1:1,
        subject:this.subject,
        score:this.score,
        date:new Date()
      })
      // 清空数据
      this.subject=""
      this.score=''
    }else{
      alert('输入格式有问题')
    }
   },
   
   FormData(dt) {
    //查文档
    return moment(dt).format('YYYY-MM-DD HH:mm:ss')
   }
  },
  computed: {
    totalScore() {
      // reduce() 累计器 常用于求和
    return  this.list.reduce((pro,item)=> pro+item.score,0)
    },
    avgScore() {
      // toFixed(2)保留两位小数 如果数组里面有长度用总分除以长度 没有则是0
      return this.list.length ? (this.totalScore / this.list.length).toFixed(2) : 0
    }
  },
  watch:{
    list: {
      deep:true, //深度监听
      handler() {
        // 复杂数据类型存储需要转字符串
        localStorage.setItem('scoreList',JSON.stringify(this.list))
      }
    }
  }
};
</script>

<style lang="less">
.score-case {
  width: 1000px;
  margin: 50px auto;
  display: flex;
  .table {
    flex: 4;
    table {
      width: 100%;
      border-spacing: 0;
      border-top: 1px solid #ccc;
      border-left: 1px solid #ccc;
      th {
        background: #f5f5f5;
      }
      tr:hover td {
        background: #f5f5f5;
      }
      td,
      th {
        border-bottom: 1px solid #ccc;
        border-right: 1px solid #ccc;
        text-align: center;
        padding: 10px;
        &.red {
          color: red;
        }
      }
    }
    .none {
      height: 100px;
      line-height: 100px;
      color: #999;
    }
  }
  .form {
    flex: 1;
    padding: 20px;
    .form-item {
      display: flex;
      margin-bottom: 20px;
      align-items: center;
    }
    .form-item .label {
      width: 60px;
      text-align: right;
      font-size: 14px;
    }
    .form-item .input {
      flex: 1;
    }
    .form-item input,
    .form-item select {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      width: 200px;
      height: 40px;
      box-sizing: border-box;
      padding: 10px;
      color: #666;
    }
    .form-item input::placeholder {
      color: #666;
    }
    .form-item .cancel,
    .form-item .submit {
      appearance: none;
      outline: none;
      border: 1px solid #ccc;
      border-radius: 4px;
      padding: 4px 10px;
      margin-right: 10px;
      font-size: 12px;
      background: #ccc;
    }
    .form-item .submit {
      border-color: #069;
      background: #069;
      color: #fff;
    }
  }
}
</style>